Well, to be fair, the Nentir Vale Pantheon's been officially written up as much as any PHB pantheon since the DMG came out. I don't know why they stuck it in the DMG and gave us all those real world pantheons in the PHB, but there you go.
Forgot to say this earlier: I really, really want a Nentir Vale sourcebook for 5e. We had what was going to be a Nentir Vale Gazetteer, a 4e analogue to the Known World Gazetteers that fleshed out the Mystara world back for BECMI, literally ready to print before Mearls ordered it cancelled. My deepest hope is that they still have it saved somewhere in the WotC archives and can use that to flesh out the world. Even if it is just a reprinting of all of the Nerathi Legends articles and the few other "regional" articles from Dragon, the Nentir Vale deserves some love.
I think it had (has?) a lot of potential. I just wasn't confident I could bring it to life. I think I also ended up laying it to the side once the finished version of 5e came out and I got swept up in running the actual published adventures instead of developing my own further.That sounds pretty awesome.
I'd like to see the devs do a more extensive separation of Nentir BANE from Realms BANE in the deity lore, unless they want to merge the two Banes, which might make people's heads explode.
They did a Deities & Demigods article on Nentir Bane - or Achra, if it's easier for you to remember - early on in 4e. It really sold him as just who he was and why.
I don't know much about Nentir Vale. What sort of things would need converting?I would love to run a 5e Nentir Vale campaign without having to do all the conversion work myself.